1. Field of the Invention
This invention relates generally to packing structures for chemical processing and heat transfer equipment and, more particularly, to packing elements for use in randomly packed beds.
2. Description of Related Art
It is known to use packing in mass transfer towers as well as in heat sink applications. Packing provides increased surface area for exchanges between liquid and vapor phases as well as for heat transfer. Packing may take the form of a fixed structure, also referred to as structured packing, or may be random or dumped packing which is placed in a tower in a random manner on a supporting surface. Different chemical processes dictate what type of packing will be used along with considerations such as energy requirements for operating an exchange tower. Random packings of the type which are the subject of the present invention are advantageous from the standpoint of being very economical to manufacture and install.
Random packings have taken many different shapes and examples of the prior art are found in U.S. Pat. Nos. 578,548; 4,203,935; and 6,547,222.
The objective of nearly all random packings is to present the largest possible surface area for either heat exchange or mass transfer. It is also desirable, however, to maximize the free space in any particular volume of packing so as to minimize the pressure drop across the packed bed. “Free space” is defined as all of the space in a given volume that is not filled with solid material. Thus, free space encompasses the space between random packing elements as well as the space within a particular element. The objectives of maximizing surface area and free space must be accomplished while maintaining sufficient structural strength that the packing elements will not collapse even when confined in an area several meters deep.
It is known to make random packing from various types of metal, from plastic and from ceramics. Ceramic packings are employed in highly corrosive environments.